Starch is another name for complex carbohydrates used by the body for fuel.
Resistant starch is exactly what the name implies — complex carbohydrates that “resist” digestion. This type of starch travels from the small intestine undigested to the large intestine, where it provides fuel for the good bacteria that live there.
When resistant starch is broken down by this intestinal bacteria, the production of short-chain fatty acids, such as butyrate, increases, which research suggests could be beneficial to health.
Resistant starch differs from regular starch, which provides the body with sugar when digested. Because resistant starch doesn’t produce sugar, it might benefit insulin resistance. It also provides fewer calories than regular carbohydrates, so it might be beneficial for weight control.
Because resistant starch helps maintain a healthy microbiome, it can benefit intestinal health, which affects every part of the body. The trillions of microbes that live in the large intestine produce chemicals that can have a positive effect on how the brain works.
Research also suggests that resistant starch might help prevent or treat Type 2 diabetes, irritable bowel syndrome and various cancers, though more studies in humans are needed to understand these benefits.
Researchers have identified five types of resistant starch. Three are naturally occurring in foods, including rice, pasta or potatoes that have been cooked and cooled, soybeans, whole grains, corn, seeds, plantains, green bananas, lentils and flours such as cassava flour, plantain flour and potato starch.
One of the remaining types can occur naturally or be manufactured. The other is completely manufactured — starch that has been altered physically, enzymatically or chemically to be used in processing foods like cakes and cookies. It’s often listed as modified food starch on ingredient labels.
Modified starches are used for the same reasons as regular starch — to thicken, stabilize or emulsify food products. Though modified doesn’t necessarily mean genetically modified, some modified starches are made from genetically modified ingredients.
Anything that has a positive effect on your intestinal tract can benefit overall health. Though there are no nutritional guidelines on this, try to include sources of natural resistant starch as often as you can in your diet.
Environmental Nutrition is a newsletter written by experts on health and nutrition.